1. Field
Embodiments of the present disclosure relate to a load detecting method, and more particularly, to a method for detecting whether a load is connected to or detached from a power supply device, and a power supply device applying the same.
2. Discussion of Related Art
It is necessary to detect whether the capacitive load is connected to or detached from a power supply device. In order to detect such connection status of the capacitive load, a predetermined signal may be applied to an output voltage fed from the power supply device. The amplitude of the applied signal (hereinbelow, ‘test signal’) is limited, as the effective switching frequency is decreased.
The output voltage from the power supply device is so controlled that it remains within a set range between maximum and minimum voltages. Even with an application of the test signal on the output voltage, the output voltage has to remain between the maximum voltage and the minimum voltage.
Given this condition, as the load decreases causing the switching frequency to decrease, the output voltage ripple from the power supply device increases and the room to add the test signal decreases. Further, since the output voltage ripple increases even in the burst mode operation for the decreasing load, the room to add the test signal decreases.